Among the conventionally-known vehicular lighting units is one disclosed in Japanese Utility Model Application Laid-open Publication No. SHO-63-72803. A rear lamp unit disclosed in the No. SHO-63-72803 publication includes a tail and stop lamp as a light source mounted to a lamp case. The tail and stop lamp is mounted obliquely outward with respect to a front-rear direction of the vehicle, and thus, the tail and stop lamp can provide illumination both rearward of the vehicle body and laterally outward of the vehicle body. Namely, the rear lamp unit functions also as a side marker light.
The vehicular lighting unit is designed to allow a person outside the vehicle (outside person) to visually recognize presence of the vehicle. As one approach to effectively allow an outside person to visually recognize the vehicle, it may be conceivable to increase the number of the tail and stop lamp to thereby provide more intense (lighter) illumination. However, merely increasing the number of the tail and stop lamp would undesirably result in an increase in size of the vehicular lighting unit.